Cooling-arrangement

ABSTRACT

A cooling-arrangement is provided. The arrangement for cooling includes a device and a heat exchanger. The device is coupled with the heat exchanger in a way, that heat, which is generated inside the device, is transferred from the device to the heat exchanger. The heat exchanger is at least partly arranged into an ambient airflow. The heat exchanger is constructed in a way that the heat is transferred from the heat exchanger into the ambient airflow. The heat exchanger contains a suction side and a pressure side, which are arranged and constructed in a way that the ambient air, which passes by close to the sides, is accelerated for an improved heat transfer.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority of European Patent Office application No. 10189995.3 EP filed Nov. 4, 2010, which is incorporated by reference herein in its entirety.

FIELD OF INVENTION

The invention relates to a cooling-arrangement, which is used in connection with a device, preferably with a wind turbine.

BACKGROUND OF INVENTION

A device like an electrical machine (generator) produces heat due to electromagnetic losses inside for example.

Heat is generated asides end-windings of a generator-coil for example. The temperature of the end-windings must be kept below a pre-determined value to ensure the lifetime of the insulated coil for example.

Even the temperature of wind turbine components needs to be monitored and regulated if needed to ensure the lifetime of the components. As wind turbines, especially offshore-wind turbines, has to show a lifetime of at least 20 years this topic needs to be addressed very carefully.

Expensive repair-work has to be avoided, especially as there is only a limited day-number where repair work can be done at an offshore wind turbine.

Different arrangements are known to cool devices like electrical machines (a generator for example). Cooling circuits with air or water may be used independently or as a combination to remove heat out from the device and to its ambient for example.

The cooling system may be placed inside the generator or on top of its housing for example. Heat exchangers are used to transfer the heat from the generator to the ambient air for example.

It is known to locate a cooling arrangement on top of the nacelle of a wind turbine for example. Heat, which is generated inside the nacelle, is transferred by a cooling system to the cooling arrangement. The cooling arrangement may use ambient air, which passes by, for the cooling.

The nacelle and even the cooling-system on its top are transported to a specific site by train or by ship or by truck. Preferably they may be connected and transported together as a common device. Along the way of transportation problems with tunnels and bridges may arise as a typical offshore-nacelle shows huge dimensions and even a huge weight.

It is therefore of great importance to have a cooling-arrangement which is able to transfer the heat of the nacelle to the ambient, while

the cooling arrangement needs to be lightweight,

the cooling arrangement needs to be connected or disconnected in an easy way with the nacelle, and/or

the cooling arrangement needs to be as cheap as possible.

All or even some of these requirements may be needed for a cooling arrangement, which is dedicated to be used in combination with a device.

SUMMARY OF INVENTION

It is therefore the aim of the invention, to provide an improved cooling arrangement, which is used to transfer heat of a device to an ambient airflow.

This aim is reached by the features of the claims.

Preferred configurations are object of the dependent claims.

According to the invention the arrangement for cooling contains a device and a heat exchanger. The device is coupled with the heat exchanger in a way, that heat, which is generated asides the device, is transferred from the device to the heat exchanger.

The heat exchanger is at least partly arranged into an ambient airflow. The heat exchanger is constructed in a way that the heat is transferred from the heat exchanger into the ambient airflow. For this the heat exchanger contains a suction side and a pressure side, which are arranged and constructed in a way that the ambient air, which passes by close to the sides, is accelerated for an improved heat transfer.

Preferably the pressure side is arranged close to the device while the suction side is arranged in opposition to the pressure side.

Due to the shaped heat exchanger the transfer of heat from the heat exchanger and into the ambient is improved.

Preferably the device is at least partly arranged into an ambient airflow. Preferably the device is a nacelle of a wind turbine, while the heat exchanger is arranged on top of the nacelle preferably.

Due to the shape of the nacelle and due to the shape of the heat exchanger and their interaction the ambient air is accelerated and used for the cooling of the nacelle.

Preferably the heat exchanger is at least partly arranged into a housing. Preferably the heat exchanger or its housing shows a cross section of an airfoil.

The structure of the airfoil is used to accelerate the ambient air. The needed dimensions for the shape of the airfoil can be calculated easily.

Preferably at least a part of the heat exchanger contains a porous material arranged at least at a section of the heat exchanger.

Preferably a like graphite foam is used as porous material for the heat-transfer to the ambient air.

Due to the porous material the heat exchanger show less weight than other known types of heat exchangers.

Due to the porous material and due to a pressure difference, which is induced between the suction side and the pressure side, an additional air flow is induced. This additional air flow is guided through the material thus the heat transfer to the ambient is improved additionally in view to the accelerated air passing by the sides of the heat exchanger.

Preferably the porous material is a high thermal conductivity material, like graphite-foam.

Due to this the complexity and even the costs asides the heat exchanger are reduced.

Preferably the device and the heat exchanger are connected by a cooling-system, which is arranged and used to transfer the heat from the device to the heat exchanger.

Preferably the cooling-system contains a tube, which is filled with a cooling fluid, like oil or water. Even air or other gases may be circulated inside the cooling system.

Preferably the cooling-system is coupled with the foam in a way that the heat is transferred from the cooling-system into the foam easily.

Due to the features cited above an easy interaction between the cooling system and the foam of the heat exchanger is achieved. The tube only needs to be arranged at least partly within the foam.

There is no need for further expensive arrangements to ensure a good thermal contact between the foam and the cooling system.

The graphite foam is a light and shows a high thermal conductivity. It is a porous material which can be easily machined and shaped.

In particular, the foam material can be shaped like an airfoil. Thus a pressure differential between the suction side and the pressure side can be made very easy.

Due to the porous material and due to the pressure difference, which is induced by the sides of the shaped heat exchanger, an additional air flow is induced. This additional air flow is guided through the porous material. Thus the heat transfer is improved additionally in view to the accelerated air, which passes by.

According to the invention preferably the nacelle of the wind turbine is the device, which needs to be cooled.

The heat exchanger may also be preferably arranged asides a blade of the wind turbine, when its nacelle needs to be cooled.

The heat exchanger might be an integrated part of the blade preferably. Thus the foam, which is used preferably asides the heat exchanger, may be arranged inside the blade for example.

The heat exchanger and the foam may even be at least partly integrated asides the blade/within the blade.

Due to the shape of the blade the incorporated foam show the same advantageous surface of the airfoil cross-section.

Due to the differential pressure asides the airfoil cross-section the flow of the ambient air is quote high.

Due to the huge surface of the blade, it is per se a very good heat exchanger.

When the wind turbine is at work also high wind-speeds are acting on the blade. Thus there is a good cooling-situation when the heat asides the nacelle (generator) is produced.

Moreover the heat transfer increases with the rotational speed of the blade and at the same time, where due to generator losses the heat sides the nacelle is increased.

The part of the blade, where the heat exchanger is arranged, is preferably connected with a “water to air heat exchanger”, which might be arranged inside the hub.

It is even possible, that a number of heat exchangers according to the invention are used in different combinations.

For example one heat exchanger asides a blade and one heat exchanger asides the nacelle, preferably on its top.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is shown in more detail by help of some figures.

FIG. 1 shows a preferred configuration according to the invention,

FIG. 2 shows another preferred configuration according to the invention, and

FIG. 3 shows a detailed view to the preferred configuration shown in FIG. 2.

DETAILED DESCRIPTION OF INVENTION

FIG. 1 shows a preferred configuration according to the invention.

For this figure the heat of a wind turbine nacelle (not shown in detail here) needs to be transferred from the heat exchanger into the ambient air.

A heat-exchanger HE is an integrated part of a blade BL of the wind turbine.

Due to the shaped blade BL even the heat exchanger HE contains a suction side SS and a pressure side PS.

They are arranged and constructed in a way that ambient air AE, which is passing by close to the sides SS and PS of the blade BL, is accelerated.

Thus the transfer of heat out of the heat exchanger HE and into the ambient air AE is improved.

The heat exchanger HE contains at least a section with a porous material HEPM.

The material HEPM shows preferably a high thermal conductivity. Graphite foam may be used as material preferably.

A pressure difference P1 and P2<P1 is induced by the two sides SS and PS of the shaped heat exchanger HE. Thus an additional air flow AAF is induced.

Due to the porous material HEPM and due to its arrangement and position within the heat exchanger HE the additional air flow AAF is guided through the material HEPM.

Thus the heat transfer is improved additionally in view to the accelerated air AE.

The heat exchanger HE contains the porous material HEPM within at least one section. The porous material may even fill the heat exchanger HE completely.

FIG. 2 shows another preferred configuration according to the invention.

A wind turbine is shown here, which contains a nacelle NA, a tower T, a hub HB and a blade BL.

The heat exchanger HE is arranged on top of the nacelle NA.

The heat of the nacelle NA needs to be transferred from the heat exchanger HE into the ambient air AE, which passes by the nacelle NA and/or the heat exchanger HE.

The heat exchanger HE is shaped according to the cross section of an airfoil. Thus the heat exchanger HE contains a suction side and a pressure side. The sides are arranged and constructed in a way that ambient air AE, which passes by close to its sides, is accelerated.

For this principle and even for the internal structure of the heat exchanger HE reference is made to the situation and to the elements used as described in FIG. 1.

Thus the transfer of heat out of the heat exchanger HE and into the ambient air AE is improved.

The heat exchanger HE may contain at least a section with a porous material. The material shows preferably a high thermal conductivity. Graphite foam may be used as material preferably.

Due to the porous material and due to the pressure difference, which is induced by the sides of the shaped heat exchanger HE, an additional air flow is induced. This additional air flow is guided through the porous material. Thus the heat transfer is improved additionally in view to the accelerated air AE.

For this principle reference is also made to FIG. 1.

FIG. 3 shows a detailed view to the preferred configuration shown in FIG. 2.

Here the heat exchanger HE is arranged inside a housing and the heat exchanger HE is shaped according to the cross section of an airfoil.

For this principle and even for the internal structure of the heat exchanger HE reference is made to the situation and to the elements used as described in FIG. 1.

The structure of the airfoil is used to accelerate the ambient air AE.

The heat exchanger HE contains a porous material HEPM, like graphite foam. The porous material is arranged at least within a section of the heat exchanger HE.

The nacelle NA and the heat exchanger HE are connected by a cooling-system PCS, which is arranged and used to transfer the heat from the nacelle NA to the heat exchanger HE. This is done by water for example, which is circulated inside the cooling-system PCS by tubes.

A water-filled tube is arranged inside the foam-material HEPM. As the material HEPM is a high thermal conductivity material the exchange of heat from the tube and into the foam is improved, too.

The heat exchanger HE is connected with the nacelle by supporting elements SSE, which might also be used as a water-inlet WI and as a water-outlet WO of the cooling-system PCS.

The heat exchanger HE contains the porous material HEPM within at least one section. The porous material may even fill the heat exchanger completely.

Due to the porous material HEPM and due to the pressure difference as described in FIG. 1 an additional air flow is induced. This additional air flow is guided through the material HEPM, thus the heat transfer is improved additionally in view to the accelerated air AE, which passes by the nacelle. 

1-13. (canceled)
 14. An arrangement for the cooling of a device, comprising: a heat exchanger coupled with the device in a way that heat which is generated inside the device, is transferred from the device to the heat exchanger, the heat exchanger comprising: a suction side, and a pressure side, wherein the heat exchanger is at least partly arranged into an ambient airflow, while the heat exchanger is constructed in a way that the heat is transferred from the heat exchanger into the ambient airflow, and wherein the suction side and the pressure side are arranged and constructed in a way that the ambient air, which passes by close to the sides, is accelerated for the heat transfer.
 15. The arrangement according to claim 14, wherein the device is at least partly arranged into the ambient airflow.
 16. The arrangement according to claim 14, wherein the heat exchanger is at least partly arranged into a housing.
 17. The arrangement according to claim 16, wherein the housing shows a cross section of an airfoil.
 18. The arrangement according to claim 14, wherein the heat exchanger shows a cross section of an airfoil.
 19. The arrangement according to claim 14, wherein the heat exchanger includes a porous material within at least a section of the heat exchanger, and wherein the porous material is arranged in a way that due to a pressure difference, which is induced between the sides of the shaped heat exchanger, an additional air flow is induced and is guided through the porous material for an additional cooling purpose.
 20. The arrangement according to claim 19, wherein the porous material is a high thermal conductivity material.
 21. The arrangement according to claim 19, wherein the porous material is graphite-foam.
 22. The arrangement according to claim 14, wherein the device and the heat exchanger are connected by a closed cooling-system, which is arranged and used to transfer the heat from the device to the heat exchanger.
 23. The arrangement according to claim 22, wherein the closed cooling-system comprises a tube, which is filled with a cooling fluid.
 24. The arrangement according to claim 22, wherein the closed cooling-system is coupled with the foam in a way that the heat is transferred from the cooling-system into the foam.
 25. The arrangement according to claim 14, wherein the device is a nacelle of a wind turbine.
 26. The arrangement according to claim 25, wherein the heat exchanger is arranged on top of the nacelle.
 27. The arrangement according to claim 25, wherein the heat exchanger is at least partly integrated in a blade of the wind turbine. 